What is the difference between EVM equivalence and Ethereum equivalence
EVM equivalent: The rollup is nearly identical to L1 Ethereum from the dapp developer perspective. Optimism has been EVM equivalent since the OVM 2.0 upgrade on November 11th, 2021.
Ethereum equivalent: The rollup is nearly identical to L1 Ethereum from the protocol developer perspective. After the bedrock upgrade (in 2022, Q4), the difference between a geth client running on L1 and one running on Optimism will be less than 500 lines of code, mostly dealing with communication between layers. So execution-layer functionality will be nearly identical. The consensus layer has to be very different in a rollup, but we are isolating that functionality into a component called the rollup node.